In wireless communication networks, such as cellular networks, a single communication channel may be insufficient to provide the performance required by certain users, such as sufficient bandwidth, mobility, full territorial coverage, sustainability of performance, and uplink capacity. To address this problem, U.S. Pat. No. 7,948,933, whose disclosure is incorporated herein by reference, describes a virtual broadband transmitting unit, in which a stream generator generates multiple data streams from an incoming media datastream. A transmission manager controls upload of the data streams via multiple modems over corresponding transmission channels to at least one wireless communication network (such as a cellular network). The data streams are reassembled into a single media stream at the receiver.
U.S. Patent Application Publication 2011/0269456 describes systems and methods of managing concurrent access using different network identities in a wireless apparatus with a shared baseband hardware implementation. Data obtained by concurrently utilizing the baseband device with different network identities. The identities may be associated with a physical subscriber identity module (SIM), also referred to as a “subscriber integrated module,” or a virtual SIM (VSIM).
A SIM is an integrated circuit embedded on a small, removable card, which is used in most mobile telephones. The SIM contains a unique serial number and an international mobile subscriber identity (IMSI), corresponding to the telephone number, as well as codes used in security authentication and ciphering, along with other critical information. The equivalents in cellular UMTS and CDMA networks are sometimes called UICC and R-USIM, respectively. Examples of other equivalents and names of corresponding entities in other sorts of networks are ISIM (IP multimedia SIM), and USIM. SIMs may also sometimes be used in satellite networks, such as BGAN Inmarsat, Thuraya, Iridium and VSAT, as well as in some WiFi networks. A VSIM serves the same purpose as a conventional SIM card, except that the SIM card itself is held in a remote server, rather than in the mobile modem, and the corresponding identity data (including the IMSI and any security information needed for proper operation) are provided to the modem as and when required.
For example, Implementa (Hannover, Germany) provides a “Virtual SIM Platform,” in which SIM cards are stored and managed in central SIM Storages and remotely utilized by mobile terminals. A single SIM card from the storages can be allocated to a mobile terminal by means of software commands. Mobile terminals with allocated Virtual SIM cards are said to behave just as if the SIM card was inserted physically in the terminal.